1. Field of the Invention
The invention relates to a method for producing a forging from a gamma titanium aluminum-based alloy.
2. Discussion of Background Information
Titanium aluminum-based alloys, which are essentially formed from intermetallic titanium aluminide, have a high melting point, low density, a high specific modulus of elasticity, good oxidation behavior, high specific tensile strength, and creep resistance in a temperature range from 600° C. to 800° C. Thus, these alloys meet the constantly increasing requirements for special materials such as, e.g., for components of the next generation of aircraft engines and internal combustion engines.
Titanium aluminide materials have not yet been optimized with respect to their alloy composition or with respect to their production and processing.
An alloy having a good workability, as well as balanced mechanical properties, can be produced by suitable heat treatments from the elements titanium, aluminum, niobium, molybdenum and boron. For this reason, it is referred to as a “TNM alloy” among experts.
Due to the intermetallic character of the titanium aluminide alloys, also optionally of the TNM materials, can be brittle in unsuitable deformation conditions. Because of this brittle behavior in such unsuitable deformation conditions, a production of forgings such as turbine blades is critical and usually associated with high waste rates.
Moreover, it is known to carry out a forged deformation under isothermal conditions. However, this requires a special high-temperature drop forge die with a protective gas atmosphere and, therefore, is expensive.